package com.hmdp.service.impl;

import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IFollowService;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

import static com.hmdp.utils.RedisConstants.FEED_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {

    @Resource
    StringRedisTemplate stringRedisTemplate;
    @Resource
    IFollowService followService;

    @Override
    public Result likeBlog(Long id) {
        //1、获取登录用户
        UserDTO user = UserHolder.getUser();
        Long userId = user.getId();
        //2、判断用户是否已经点赞
        String key = "blog:liked:"+id;
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        if(score==null){
            //3、未点赞，进行点赞操作
            //3.1 数据库点赞数+1
            boolean isSuccess = update().setSql("liked = liked + 1").eq("id", id).update();
            //3.2 将用户添加到redis的set集合中
            if(isSuccess){
                stringRedisTemplate.opsForZSet().add(key,userId.toString(),System.currentTimeMillis());
            }
        }else{
            //4.已点赞，取消点赞
            //4.1 数据库点赞数-1
            boolean isSuccess = update().setSql("liked = liked - 1").eq("id", id).update();
            //4.2 移除redis的set集合中的用户
            if(isSuccess){
                stringRedisTemplate.opsForZSet().remove(key,userId.toString());
            }
        }

        return Result.ok();
    }

    @Override
    public Result saveBlog(Blog blog) {
        // 获取登录用户
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());
        // 保存探店博文
        boolean isSuccess = save(blog);
        if(!isSuccess){
            return Result.fail("新增笔记失败");
        }
        //查询笔记作者的所有粉丝
        List<Follow> follows = followService.query().eq("follow_user_id", user.getId()).list();
        //推送笔记id给所有粉丝
        for (Follow follow : follows) {
            //获取粉丝id
            Long userId = follow.getUserId();
            //推送
            String key = FEED_KEY+userId;
            stringRedisTemplate.opsForZSet().add(key,blog.getId().toString(),System.currentTimeMillis());
        }
        //返回id
        return Result.ok(blog.getId());
    }

    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        //1、获取当前用户
        Long userId = UserHolder.getUser().getId();
        //2、查询收件箱 【滚动分页查询】
        String key = FEED_KEY+userId;
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet().reverseRangeByScoreWithScores(key, 0, max, offset, 2);
        if(typedTuples == null || typedTuples.isEmpty()){
            return Result.ok();
        }
        //3、解析数据：blogId、score（时间戳）、offset
        List<Long> ids = new ArrayList<>(typedTuples.size());
        long minTime = 0;
        int os = 1;
        for (ZSetOperations.TypedTuple<String> tuple : typedTuples) {
            //获取id
            ids.add(Long.valueOf(tuple.getValue()));
            //获取分数（时间戳）
            long time = tuple.getScore().longValue();
            if(time == minTime){
                os++;
            }else{
                minTime = time;
                os = 1;
            }
        }
        //4、根据id查询blog
        String idStr = StrUtil.join(",",ids);
        List<Blog> blogs = query().in("id",ids).last("REDER BY FIELD(ID,"+idStr+")").list();

        //5、封装并返回
        ScrollResult r = new ScrollResult();
        r.setList(blogs);
        r.setOffset(os);
        r.setMinTime(minTime);

        return Result.ok(r);
    }
}
